1. Field of the Invention
The present invention relates to a pneumatic tire,
2. Related Art
A plurality of main grooves extending in a tire circumference direction segmentalize a tread to form a center land, portion inside in a tire: width direction and shoulder land portions outside in the tire width direction. Depending on the tires, a shoulder land portion is formed into a rib continuing in the tire circumference direction. However, as described in Japanese Patent No. 4149219 and Japanese Patent No. 4330561, there is a fire in which the shoulder land portion is segmentalized by a plurality of lateral grooves extending in the tire width direction to form a block row. As illustrated in Japanese Patent No. 5160243, there is also a tire in which the shoulder land portions are segmentalized by the lateral grooves arranged alternately on the main groove side and the tire ground contact end side and narrow grooves extending in the tire circumference direction to form the block row in a zigzag pattern.
The tire having the block row includes the lateral grooves, and thus tends to have excellent traction properties. If the lateral grooves are deep, the lateral grooves remain being deep even though wear of the tread has become advanced, and the traction properties are ensured.
Since the shoulder land portions are subjected to a significant lateral force from the tire ground contact end sides, wear and uneven wear ar:e likely to become advanced. Therefore, it is important to ensure wear-resistance properties and uneven-wear-resistance properties of the shoulder land portions. However, since blocks are low rigidity and thus are more likely to move compared with a rib continuing in the tire circumference directions, and the shoulder land portions having the block row may be poor in wear-resistance properties and uneven-wear-resistance properties in some cases. In particular, in the case where the lateral grooves are deep, the wear-resistance properties and the uneven-wear-resistance properties are more likely to become poor. In this manner, in the related art, nevertheless wear-resistance properties and uneven-wear-resistance properties are important for the shoulder land portions, the wear-resistance properties and the uneven-wear-resistance properties cannot be secured easily when traction properties are ensured.